Effects Of Roots Exudating Organic Acids Of Malus Hupenensis Rehd Induced By Leaching Liquor Of Roots And Soil From The Update Orchard

The rate of organic acids in allelochemicals of root exudation accounts for33percent.Organic acids secreted by plants have an obvious effect upon plants, biological growth, andsoil conditions, such as phydroxybenzoic acid, ferulic acid, cinnamic acid, benzoic acid, etc.,can inhibit seed germination, root growth. The effects of leaching liquor of root and soil fromthe update orchard on seedlings growth of Malus hupenensis Rehd were studied by using themethods of sand culture, in the first15days,30days,45days,60days, Root exudation werecollected, the amount and changes were analysised by HPLC. Connection between differentconcentration of soil, root leach liquor and physiological index in different period, effect ofdifferent concentrations of soil, root leaching liquor on root secreting organic acid wereobtained to improve the causes and amelioration of continuous cropping stress. The resultswere as follows:（1） Low concentration of root leaching liquor （A1）, soil leaching liquor （B1） significantlyimproved plant growth, chlorophyll synthesis production; high concentrations (A6, B_4-6)treatment inhibited growth, allelopathy was the strongest in the30d. All of the root leachingliquor treatment and high concentrations of soil leaching liquor （B5, B6） inhibited the stemdiameter, the higher the concentration the stronger the inhibition, and RI of A6was0.74, RI ofA6was0.53on average in60d.（2） A1played a great role in promoting root elongation; in the60d, root length, diameter wasmost significant promoted, separately increase19.56%,23.47%; in the15d, tip number wassignificant increased15.96%compared with CK; A_4-6, B_4-6significantly inhibited root growth,the inhibition has a positive relationship with treatment concentration.（3） A1increased POD, CAT activity; A4decreased POD activity; A4, A5decreased SODactivity; A4-6decreased CAT activity. Low concentrations of soil leaching liquor had nosignificant effect on the POD, SOD, CAT activity; B5, B6decreased POD, SOD, CATactivity.（4） Low concentration of roots, soil leaching liquor had no significant effect on Fv/Fm, qP, NPQ; A_5-6, B_5-6significantly decreased Fv/Fm and qP values, increased NPQ value.（5） At the end, all of the roots, soil leaching liquor treatment inhibited the secretion of gallicacid, hydroxybenzoic acid, benzoic acid, phloridzin; promoted the secretion of caffeic acid.Atthe same time, roots leaching liquor treatment inhibited the secretion of Catechin, promotedthe secretion of phloretin; soil leaching liquor treatment promoted the secretion of cinnamicacid. other phenolic acid secretion due to the different concentration of different functions.